1. Field of the Invention
The present invention relates to a device for indirectly detecting a casing breakage during material stuffing in a stuffing apparatus for manufacturing sausages, fish feeds, or the like.
2. Description of the Related Art
Sausage products are manufactured by stuffing a material such as meat, i.e., a stuffing material, into an artificial casing such as a cellulose casing or a collagen casing or a casing of an animal intestine such as a sheep intestine or a hog intestine. In addition, sausage-like assorted feeds in which a material stuffed in a collagen casing are manufactured as feeds for cultured tuna.
FIG. 15 shows a conventional stuffing apparatus. A stuffing apparatus 1 includes, among others, a stuffing nozzle 3 for feeding a material such as meat, i.e., the stuffing material, into a casing 2; a stuffing pump 4 for feeding the material into the stuffing nozzle 3; a stuffing nozzle rotating means 5 for rotating the stuffing nozzle 3; a braking mechanism 6 which is engaged with the casing 2; and a pincher device 8 for feeding a stuffed casing 7 with the material filled therein forwardly (in a direction away from the stuffing nozzle 3) and pinching it.
Further, the material is fed from the stuffing pump 4 into the stuffing nozzle 3, and while the shirred casing 2 loaded on the outer periphery of the stuffing nozzle 3 is being rotated together with the stuffing nozzle 3 and the braking member 6, the material in the stuffing nozzle 3 is filled into the casing 2 pulled out and stretched forwardly. Further, the stuffed casing 7 with the material filled therein is pinched by the pincher device 8, and a twist is formed in that pinched portion by the rotation of the stuffing nozzle 3 and the like, to thereby manufacture a sausage product or the like.
It should be noted that a trailing end portion 2a of the shirred casing 2 is pushed forwardly by a casing pusher 9. Further, when a terminating end of the trailing end portion 2a of the shirred casing 2 is detected by an optical sensor 10, and the optical sensor 10 detects the terminating end, the stuffing apparatus 1 is stopped (refer to Japanese Patent No. 3723656 corresponding to U.S. Pat. No. 5,788,563).
Incidentally, an artificial casing or a natural intestine casing of an animal intestine is formed in a shirred state, is loaded in that shirred state on the outer periphery of the stuffing nozzle, and is stretched by the pincher device during stuffing, and the material, i.e., the stuffing material, is stuffed into its interior. For this reason, if any slight damage is caused to the casing such as when the casing is stretched, there are cases where the damage during the stuffing of the material spreads, and the casing becomes ruptured and breaks.
The stuffing apparatus is in many cases operated automatically, and if the casing brakes during the stuffing of the material, unless the stuffing pump for feeding the material is stopped, the material continues to be discharged from the discharge port of the stuffing nozzle, impinges against the pincher device, and scatters to the surroundings. Particularly in the case of automatic operation, an operator, upon noticing a casing breakage, will press a stop switch, but the time duration when the operator is away from the stuffing apparatus is often long, so that the operator is inevitably apt to be delayed in noticing such a casing breakage. A further delay in noticing results in more material being discharged to the outside and wasted, and time and trouble are required in cleaning up the discharged material, causing production efficiency to decline correspondingly.
In addition, in the case of manual operation, the operator is able to notice a casing breakage more speedily and is able to press the stop switch quickly. This being the case, however, the material continues to be discharged to the outside until the operator presses the stop switch after noticing, so that the material is wasted by that quantity. The time and trouble for cleaning up the discharged material are also required, so that there is still a problem in that the production efficiency declines.
As an apparatus for overcoming such a problem, an apparatus disclosed in JP-UM-B-6-29989, for instance, is known. This apparatus has an optical vision sensor 17 provided forwardly above the stuffing nozzle to monitor the stuffed casing by this vision sensor 17, and in the event that the casing is broken and the material has jumped out, the vision sensor 17 detects it and the stuffing apparatus is stopped.
In addition, an apparatus disclosed in JP-T-2004-524008 (corresponding to U.S. Pat. No. 6,558,241), for instance, is known. In this apparatus, an optical or mechanical sensor 34 is provided above the pincher device disposed forwardly of the stuffing nozzle to monitor the uniformity of the diameter of the stuffed casing by this sensor 34, and in a case where an abnormality in the casing diameter is detected, the stuffing apparatus is stopped.
The apparatus disclosed in JP-UM-B-6-29989 has a sensor provided above a discharge port of the stuffing nozzle to directly detect a rupture of the casing. However, the place of installation of the sensor is difficult to secure above the discharge port of the stuffing nozzle, and even if it is possible to secure the place of installation of the sensor, there arises a need to provide an exclusive sensor supporting means consisting of, for example, an L-shape or the like and to mount the sensor on that supporting means. Therefore, the production cost increases correspondingly.
In addition, the vicinity of the discharge port of the stuffing nozzle is a place where an operation by the operator is performed at the time of setting a new casing on the stuffing nozzle, so that there is a large risk that the material and the like attached to the operator's hand or the like become splattered. Namely, the apparatus disclosed in the above-described JP-UM-B-6-29989 has a possibility that the material and the like adheres to a sensor detecting portion such as during the stuffing operation or the setting of a new casing, rendering the sensor undetectable.
Furthermore, with the apparatus disclosed in the above-described JP-UM-B-6-29989, in the event that the casing is ruptured and the material is splattered, there is a large risk of the material adhering to the sensor. Consequently, cleaning of the sensor and its surroundings becomes essential before a new casing is loaded and an ensuing operation is started. Since that much time is involved until the ensuing operation, there is a problem in that the production efficiency declines.
The apparatus disclosed in JP-T-2004-524008 also has a virtually similar problem. Namely, the apparatus disclosed in JP-T-2004-524008 has a sensor provided above the pincher device located forwardly of the stuffing nozzle to directly detect a rupture or the like of the casing. Although the sensor is mounted on a cover 26, an exclusive sensor supporting means is required for mounting it, so that the production cost increases correspondingly.
In addition, as described above, the surrounding area of the pincher device is a place where there is a large risk of the material or the like being splattered, so that the apparatus disclosed in JP-T-2004-524008 also has a possibility that the material or the like is adhered to the sensor during the stuffing operation, thereby making detection impossible.
Furthermore, with the apparatus disclosed in JP-T-2004-524008, in the same way as the apparatus of JP-UM-B-6-29989, in the event that the casing is ruptured and the material is splattered, cleaning of the sensor and its surroundings becomes essential before a new casing is loaded and an ensuing operation is started. Since that much time is involved until the ensuing operation, there is also the problem that the production efficiency declines.
In an apparatus disclosed in JP-A-8-103206 (corresponding to U.S. Pat. No. 5,830,050), a rotary roller 15 is provided on the outer periphery of the casing which is located slightly rearwardly of the discharge port of a stuffing nozzle 3 and is set in a deshirred state. Further, a sensor 16 is provided above this rotary roller 15, and the rotation of the rotary roller 15 is detected by this sensor 16 to indirectly detect a casing breakage.
However, with the apparatus disclosed in JP-A-8-103206, the sensor 16 is provided for the discharge port of the stuffing nozzle 3 in the same way as the apparatuses of JP-UM-B-6-29989 and JP-T-2004-524008, so that the place of its installation is subject to restriction, and a special mounting means is required. Hence, the production cost increases correspondingly. Furthermore, there is a possibility that the detecting portion of the sensor becomes stained by the material or the like, rendering detection difficult.
In an apparatus disclosed in U.S. Pat. No. 4,602,402 (corresponding to JP-A-59-183646), an advance mechanism 13 engaged with a rear end 11 of a casing 10 is connected to a monitoring means 19 for monitoring the advancing movement. When the casing ruptures, the advancing movement of the casing is interrupted, and the advancing movement of the advance mechanism 13 connected to a working cylinder 17 is stopped, with the result that a pulse signal from the monitoring means 19 becomes extinct. By detecting the extinction of this signal, this known apparatus indirectly detects a casing breakage and stops a pump driving means.
However, in the same way as the apparatus disclosed in JP-A-8-103206, the apparatus disclosed in U.S. Pat. No. 4,602,402 also requires a device for converting the advancing of the casing into a pulse signal, so that the structure becomes complex by that portion, and the production cost increases correspondingly.